It should be fine. The binding is strong enough to prevent distortion from any shrinkage of the selvedge. It would be a good idea to clip the selvedge every once in awhile, inside the seam allowance.
Welcome to the Quilting Board!

It should be fine. The binding is strong enough to prevent distortion from any shrinkage of the selvedge. It would be a good idea to clip the selvedge every once in awhile, inside the seam allowance.
I like to have the backing about 4 inches bigger that the top, all the way around my quilt. This allows for the quilting. I also like to hand quilt and for that reason alone, I would cut off the salvedge edge.
It will be fine especially with the clipping as was suggested. Salvages today aren't like they used to be.
I agree and the higher the loft of the batting, the greater the problem will be. Lots of people are using pieced backs these days. Are you quilting this yourself? As a long arm quilter I could not in good conscience accept a back that small because I know the results would be less than optimal.
everyone else has answered exactly how I would have. It is best not to use it, (when I was a home ec ed major, that was the one really big thing we learned. it WILL shrink and distort your project. clipping it should help in this emergency situation, but I would recommend NOT making it a habit to leave the selvage in your project. Can't wait to see pics of the finished quilt!
Can you cut the backing in half and use some scraps to create an "artistic strip" to place in the center that would add a few inches to the width of the backing? Or you could even add a couple of inches to each side of the backing with strips made from the leftover top.
Oh well yes, I've done it. its not the best situation but who cares. Unless your sending this quilt to a national quilt show I'm pretty sure the quilt police won't issue a ticket.
I've left the selvedge on many times, and have never had a problem. Long arm quilting is another story. They need more fabric to start the quilting.
Mavita
My query would be do you fall in the prewash camp? If so don't worry about it, look at all the selvedge quilts Karen Griska has introduced and spawned.
I used a ton of selvedges in last years Bonnie Hunter mystery in the strippy blocks, and they are all fine. But I'm a prewasher.
That said I've never seen a selvedge shrink up in 40 years of prewashing. That is where we'd see it first. This might be an old myth. I do know with hand quilting they are a little harder to quilt through.